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Cautery and Electrosurgery

The concepts of “cautery” and “electrosurgery” are often considered interchangeable, but are very different tools. Both, however, are used in the gastroenterology suite, and although they are valuable helps for the staff, they carry their own specific risks for both patients and the healthcare workers using them.

Risks

One of the most serious risks is fire. According to the American College of Surgeons Committee on Perioperative Care, there are 27 million surgical operations each year in the United States, and approximately 2,260 reported hospital fires. These result in about one death and 130 injuries. Of these, between 20 and 30 occur in the operating room (OR).1

For any fire to occur, three factors must be present: oxygen, fuel, and ignition. In the operating room, these are all abundantly available. And although many endoscopy procedures are performed in a procedure room, not the OR, this setting still provides risk as well.

Courtesy of Boston Scientific

How many of your patients receive supplemental oxygen? The use of additional oxygen in an operating room automatically raises the risk. Other sources of oxygen can include nasal cannulae, nebulizers, and oxygen cylinders.

“The use of the lowest possible inspired oxygen concentration that still ensures adequate oxygen saturation is an effective means of controlling excess oxygen accumulation. Another effective means is administering oxygen along with a nonflammable gas such as helium or nitrogen. Nitrous oxide, historically used by anesthesiologists, should not be used to dilute oxygen because it does not improve the safety of delivered oxygen. It too can serve as an oxidizing agent, further propagating fires,” the American College of Surgeons recommends.

There are many possible sources of fuel in the healthcare setting. More obvious sources include paper and cloth drapes, antiseptic skin agents, endotracheal tubes, and other breathing apparatus such as nasal cannulae and plastic masks. Cloth and paper drapes are ignitable by such common operating room utensils as electrocautery.

The hazard has been increased by more frequent use of disposable drapes. Although they are less expensive and more water-resistant than traditional drapes, the disposable versions burn more easily, even if treated with flame-retardant materials. In 19 3, disposable paper drapes treated with flame retardant chemicals were ignited by a defective electrocautery device during a laparoscopic operation. The staff could not extinguish the fire and removed the drapes from the patient. They continued to burn, and filled the OR with smoke, forcing its evacuation. The patient suffered second-degree burns of the hand and third-degree burns of the thigh.2

Of note, antiseptic skin agents and endotracheal tubes can also be flammable, depending on their composition. In 1991, a fire occurred during a tracheotomy after the patient was intubated and ventilated with 100 percent oxygen. Electrocautery was used for coagulation while entering the trachea. The tracheal tube ignited with an explosion, eventually melting and perforating.3

Gastrointestinal gases can also serve as a fuel. Hydrogen and methane are extremely flammable and are produced by bacteria in the gastrointestinal (GI) tract. They can be produced in quantities of up to 200 ml per day, 40 percent of which are contained in the large intestine. If in an environment of at least 5 percent oxygen, hydrogen can explode at concentrations between 4 percent and 72 percent, while methane can explode at concentrations between 5 percent and 15 percent. Of note, the concentration of oxygen in the colon is normally 5 percent, but increases when oxygen or nitrous oxide are administered during anesthesia.4

Pyloric stenosis or intestinal obstructions can increase the amount of GI gas in the bowel due to stasis or bacterial overgrowth. Electrocautery (monopolar, bipolar, and battery-operated) units are known ignition sources.

Safety measures include the following:

Keep the fuel source, ignition mechanism, and oxygen source separate.

Keep the electrocautery tip in the holster if it is not being used.

Use only appropriately protected endotracheal tubes when operating near the trachea.

Use air or air and oxygen mixtures in anesthetic gases.

Avoid tenting drapes in a manner that allows for accumulation of oxygen or other flammable gases.

Use fire-retardant surgical drapes.

ECRI, a non-profit agency, offers a poster, “Only you can prevent surgical fires,” available at www.mdsr.ecri.org/static/surgical_fire_ poster.pdf.

Shocks are another risk associated with the electrocautery tool. “Shocks to the patient or healthcare worker can happen due to the nature of electricity,” says Melissa Fischer, RN, BSN, CNOR, clinical education specialist at Megadyne Medical Products, Inc. “One of the ways to reduce the risk of shocks is to have routine inspections of the generator and all reusable cords and cables. The physician should only activate the electrode when it is in close proximity to the tissue. Always use the lowest power settings possible and store the electrode in a safety holster or away from the patient when not in use.”

Applications

Cautery and electrosurgery are two distinctly different modalities, Fischer points out. “Cautery is the use of electricity to heat an object that is then used to burn a specific site. Electricity is not passing through the patient’s body. Branding irons are a good example of cautery. In surgery, cautery is used in the form of a battery-operated hot wire that is frequently used in ophthalmology procedures. I am not aware of traditional cautery having much if any use during endoscopic procedures today.”

Electrosurgery uses an electrical current that must pass through the tissue in order to achieve the desired effect, she explains. “Alternating current enters the patient’s body at a high density and leaves the body at a low density. This is achieved through use of a generator that converts wall current at 0 cycles to a high-frequency waveform of over 300,000 cycles per second. This conversion prevents nerve and muscle stimulation and electrocution because it is above the level of neuro-stimulation.”

There are two basic types of electrical circuits: monopolar and bipolar. “Monopolar describes an electrosurgical technique in which the tissue effect takes place at a single active electrode, and is dispersed back to the generator by a patient return electrode that completes the circuit. The generator sends the current through an attached cord or cable to the active electrode, which is controlled by the surgeon or physician. The resistance of the patient causes heating that results in the desired clinical effect. The electricity must then return to the generator without causing injury upon exiting the patient. This is accomplished by use of a return electrode which may be either an adhesive ‘grounding’ pad or a large, reusable pad. The pad must be of the proper size to ensure that there is no patient injury,” Fischer says.

Bipolar describes an electrosurgical technique in which the effect takes place between paired electrodes placed across the tissue to be treated. Typically, the instruments are in the form of forceps. No patient return electrode (grounding pad) is required for the bipolar form of electrosurgery.

“The generator can produce a variety of waveforms that create different tissue results such as cutting, coagulation, and blend cycles,” she adds. “The cutting cycle will allow the tip to cut through tissue but provides very little hemostasis. The coagulation cycle provides the greatest level of hemostasis but does not allow for smooth cutting. The blend cycle is a cutting cycle that has a reduced percentage of duty cycle that allows for some hemostasis to occur.

Monopolar and bipolar electrosurgery are often found in the outpatient setting and are used in approximately 0 percent of all surgical procedures. Specific to GI and endoscopy, electrosurgery is used in the removal of tumors, polyps, or other lesions, or in ablation-type procedures, Fischer points out. “Typically, this is done with a snare or biopsy forceps. Electrosurgery will also be used in procedures in which unexpected bleeding requires intervention.”

Cautery has been used for thousands of years, since cavemen discovered that a burning stick could stanch bleeding and seal off a wound. But electrosurgery had its beginning back in the 1920s when William T. Bovie and Harvey Williams Cushing worked together to bring the first electrosurgical generator to market. “Compared to cautery, electrosurgery enabled the surgeon to perform procedures in less time with reduced blood loss and also allowed some previously inoperable patients to be treated,” Fischer recounts.

“The use of electro-cautery probes for hemostasis has been a standard of care for many years,” says Tom Martin, global product manager at Boston Scientific Endoscopy. “Cautery is used to prevent bleeding or address bleeding in the upper and lower GI tract. Polyp removal is a typical procedure in which cautery is used to cut the polyp free of the GI tract while also sealing the blood vessel, preventing bleeding. If the blood vessel begins to ooze or leak, it can be cauterized again.”

However, “there are limits to how much cautery may be applied. Tissue type and density are determining factors in the effectiveness of cautery — too much cautery can lead to a perforation,” he observes.

Modern medicine features hundreds of different designs, lengths, and shapes of active electrodes to meet the requirements of physicians and procedures such as those encountered in laparoscopic and endoscopic cases. “Generators have advanced to solid state technology with proprietary waveforms and settings for specific surgical specialties and situations. Specialized stand-alone generators have been designed utilizing unique waveforms that allow the surgeon to seal vessels and ablate tissue. Return electrodes have built-in safety features, reducing the risk of patient injury and improving patient comfort,” she adds.

Advances in Technology

Technology has advanced in the area of patient return pads, or grounding pads or plates. “The ideal patient return pad is patient-safe, cost-effective, and diminishes the risk of the patient developing an area of skin breakdown,” says Fischer. “Some patient return pads have a strong adhesive to hold the pad in contact with the patient. These adhesives can contribute to skin problems, including allergic reactions, skin tears, and skin irritation. These pads also require careful site selection and should not be placed over excessive hair, bony prominences, fluid, scar or adipose tissues, and prostheses.”

Megadyne offers the MegaSoft™ Reusable patient return electrode, which is designed to safely disperse electrosurgical energy. There is also a viscoelastic polymer layer within the pad to reduce pressure points, friction and shearing. There is no patient prep required and the patient does not have to be in direct contact with the pad.

However, “new technologies such as mechanical clipping and argon plasma coagulation have become very popular recently, threatening traditional therapies like electro-cautery probes,” he says. “It is expected that electro-cautery probe use will begin to decline as the adoption of mechanical clipping accelerates. Several studies suggest clipping is much more effective than probes at stopping bleeding and preventing the reoccurrence of bleeding.”

Grounding pads, used in monopolar electrosurgery, are prone to falling off the patient, which can create an unsafe condition, he points out. “While highly unlikely, it is possible for the monopolar energy to leak into the treatment table or pass into the treating clinicians.”

New electrosurgical generators, such as the Boston Scientific Endostat III, incorporate a grounding pad monitoring circuit that continuously monitors the integrity of the grounding pad to ensure the patient and clinical staff remain safe at all times. Any loss of grounding pad integrity greater than 25 percent will automatically shut off power to the device until the fault-condition is corrected (the grounding pad reattached), and an audible and visual alarm accompany this action, Martin explains.

In the Injection Gold Probe and Gold Probe Bipolar Hemostasis catheters, the gold tip is designed to provide excellent conductivity, uniform burn, and effective coagulation. The system is also set up with unique integrated injection and thermal hemostasis capabilities.

Ultimately, says Fischer, all of these tools serve to improve patient safety. “The key to preventing injury and electrosurgical fires is being aware of the risk and having the knowledge to keep the injury from occurring,” she concludes.